This proposal aims to determine the kinetics of in vivo cerebral glucose uptake and utilization in health humans and to compare cerebral glucose concentration in IDDM and nondiabetic subjects. All experiments will be performed under strictly controlled metabolic conditions using high field (4 Tesla) magnetic resonance spectroscopy to measure the intracerebral glucose concentrations which is then used to calculate the rates of cerebral glucose transport and metabolism. The specific aims of the project are to determine: 1) the kinetics of glucose-mediated cerebral glucose uptake in healthy humans and to compared kinetics in the occipital cortex and the periventricular white matter; 2 whether the intracerebral glucose concentrations are comparable in normal controls Qld. in subjects with IDDM when measured at the same plasma concentrations of glucose and insulin. The completion of these studies should allow one to define the kinetics of in vivo cerebral glucose uptake and metabolism in humans for two regions of the brain and the effects of antecedent chronic hyperglycemia on cerebral glucose uptake and metabolism in subjects with diabetes. It is hoped that the application of such knowledge to the care of diabetic patients, should decrease their risk of cerebral dysfunction and of hypoglycemia unawareness.